1. Field of the Invention (Technical Field)
The present invention relates to the use of an apparatus for separating magnetic pieces of scrap-material of a first group from magnetic pieces of scrap-material of a second group, wherein a mixture of pieces of scrap-material from the first group and from the second group is collectively transported with a conveyor to a separating zone, in which separating zone the pieces of scrap-material are subjected to forces induced by a magnetic field and to gravitational forces.
2. Description of Related Art
A method of separating magnetic pieces of scrap-material of a first group from magnetic pieces of scrap-material of a second group is known from U.S. Pat. No. 6,364,117.
In the known method pieces of material, at least some of which are magnetic pieces, are separated from other pieces of material. In particular it is known from the prior art that iron sheets are separated from wasted iron products, which are parts of wasted electric products such as air-conditioners or refrigerators. In the prior art a mixture of sheet shaped scrap and ferrous cast blocks are transported by a moving conveyor and subjected to a magnetic force above the conveyor in order to re-cycle suitable iron pieces so as to be thrown into a furnace and recycled as cast material. The magnetic field provides an upwardly directed force to the magnetic pieces of material which is used to effect a separation between the sheet shaped scrap and the ferrous cast blocks. The separation is occasioned by the circumstance that the magnetic force applied on the sheet shaped scrap is stronger than the force on the same weight cast block.
Although it is possible according to U.S. Pat. No. 6,364,117 to separate different pieces of magnetic material from each other, it is still required that the first group of magnetic pieces of material distinguishes strongly from the second group of magnetic pieces of material so as to be able to effect a reliable separation. Notably sheet shaped scraps have quite different characteristics than ferrous cast blocks, in view of which it is possible to separate them from each other.
EP I 878 505 discloses an apparatus having a separating zone for separating magnetic pieces of scrap-material of a first group from magnetic pieces of scrap-material of a second group, which apparatus further comprises a conveyor for transporting a mixture of said pieces of scrap-material from the first group and from the second group to the separating zone, at which separating zone the mixture of pieces of scrap material is subjected to a magnetic field and wherein at the separation zone the conveyor is supported by a drum around which the conveyor passes at a pre-defined speed so as to impart on the mixture of magnetic pieces of scrap-material a pre-defined horizontal velocity at which said pieces are released from the conveyor at said separating zone so as to subject the pieces of scrap-material to forces induced by the magnetic field and to gravitational forces. The mixture of scrap-material concerns a first group of liberated scrap, that means fragments which essentially do not contain materials other than iron and steel, and a second group of non-liberated scrap that means fragments that do also contain other materials, in particular copper.